Sung Ji-hyun achieved a career-high world ranking of number two on March 16, 2017, distinguishing herself as a dominant force in women’s singles badminton. Making her professional debut at the 2009 Korea Open, she quickly carved a niche by specializing in singles, a focus that set her apart within the South Korean badminton landscape. Her early successes included two World Junior Championships Silver Medals in the mixed team category (2007, 2008) and an Asian Junior Championships Silver Medal (mixed team) in 2008. She was also a pivotal member of the South Korean national team that secured a gold medal at the 2010 Uber Cup, a bronze medal at the 2010 Asian Games, and a bronze medal at the 2011 Sudirman Cup.
Building on this momentum, Sung Ji-hyun garnered 10 BWF Grand Prix titles and reached 3 finals throughout her career. Notable individual victories included consecutive Korea Grand Prix Gold titles in 2011 and 2012, and multiple Chinese Taipei Open Grand Prix Gold wins in 2011, 2013, and 2014. In 2013, she claimed gold medals in both women’s singles and mixed team at the Summer Universiade, followed by an Asian Championships Gold Medal in women’s singles in 2014. Her consistency was further highlighted with a silver medal in the women’s team event at the 2014 Asian Games and a bronze medal at the 2015 BWF World Championships in Jakarta.
In 2019, Sung Ji-hyun secured the BWF World Tour Chinese Taipei Open Super 300 title, followed by a silver medal at the Asia Team Championships in 2020. Over her distinguished career, she recorded 384 wins and 207 losses in women’s singles, accumulating career prize earnings of $720,521. After retiring from playing, she transitioned into coaching, most notably mentoring fellow South Korean badminton player An Se-young, further contributing her expertise to the sport.